KELATION TO ENVIRONMENT 



519 



Odors. The characteristic odors of flowers are also associated 

 with the visits of insects. While these are usually pleasant, many 

 flowers develop odors sug- 

 gestive of carrion, and are 

 exceedingly offensive. Such 

 flowers are commonly dull- 

 colored, often marked with 

 livid blotches or veins, like 

 dead animal bodies, and 

 attract carrion insects, espe- 

 cially flies and carrion 

 beetles, which sometimes lay 

 their eggs upon them and 

 are the agents in pollination. 

 Among these ill-scented 

 flowers are many Aracese, 

 species of Stapelia, Smilax, 

 Trillium erectum, Aristolo- 

 chia, and others. 



Nocturnal Flowers. Night- 

 blooming flowers are very 

 generally white or light 

 yellow in color, and often 

 heavy-scented, the odor being 

 especially noticeable at night. Among the most conspicuous of the 

 nocturnal insects which are important agents in the pollination 



FIG. 487. A, Anemone coronaria, with peta- 

 loid sepals, s. B, Cornus jforida, the incon- 

 spicuous flowers,./?, surrounded by large peta- 

 loid bracts, b. C, Richardia sEthiopica ; sp, 

 the showy bract (spathe) surrounding the 

 inflorescence. 



FIG. 488. Primula polyantha. Showing dimorphic flowers. (After BAILEY.) 



of these flowers are the hawk-moths, or Sphingidse, which are espe- 

 cially adapted to such tubular flowers as Honeysuckle and Evening- 

 primrose. The long, slender, tubular flowers of such plants are 



